U.S. patent application number 15/057558 was filed with the patent office on 2016-09-08 for liquid ejecting head.
This patent application is currently assigned to SEIKO EPSON CORPORATION. The applicant listed for this patent is SEIKO EPSON CORPORATION. Invention is credited to Eiju Hirai, Yasuhiro Itayama, Masao NAKAYAMA, Toshihiro Shimizu, Motoki Takabe.
Application Number | 20160257119 15/057558 |
Document ID | / |
Family ID | 56843919 |
Filed Date | 2016-09-08 |
United States Patent
Application |
20160257119 |
Kind Code |
A1 |
NAKAYAMA; Masao ; et
al. |
September 8, 2016 |
LIQUID EJECTING HEAD
Abstract
A liquid ejecting head includes a piezoelectric element that is
disposed on a flow passage formation substrate, and discharges
liquid from nozzle openings through the nozzle openings by
pressurizing the liquid which fills the inside of a pressure
generating chamber due to the displacement of a vibration film
according to driving of the piezoelectric element, the
piezoelectric element includes an insulating film formed on the
vibration film, a first electrode film formed on the insulating
film, a piezoelectric layer formed on the first electrode film, and
a second electrode film formed on the piezoelectric layer, and the
insulating film includes a lower insulating film formed on the
vibration film and an upper insulating film which is formed on the
lower insulating film with the same material as that of the lower
insulating film, but has a different crystal structure.
Inventors: |
NAKAYAMA; Masao;
(Shiojiri-shi, JP) ; Hirai; Eiju; (Minowa-machi,
JP) ; Shimizu; Toshihiro; (Fujimi-machi, JP) ;
Takabe; Motoki; (Shiojiri-shi, JP) ; Itayama;
Yasuhiro; (Chino-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEIKO EPSON CORPORATION |
Tokyo |
|
JP |
|
|
Assignee: |
SEIKO EPSON CORPORATION
Tokyo
JP
|
Family ID: |
56843919 |
Appl. No.: |
15/057558 |
Filed: |
March 1, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B41J 2/1623 20130101;
B41J 2/1632 20130101; B41J 2/1646 20130101; B41J 2/1629 20130101;
B41J 2202/03 20130101; B41J 2202/11 20130101; B41J 2/161 20130101;
B41J 2/14233 20130101 |
International
Class: |
B41J 2/14 20060101
B41J002/14 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2015 |
JP |
2015-041542 |
Claims
1. A liquid ejecting head comprising: a piezoelectric element that
is disposed on a flow passage formation substrate, wherein the
liquid ejecting head discharges liquid from nozzle openings through
the nozzle openings by pressurizing the liquid which fills an
inside of a pressure generating chamber due to displacement of a
vibration film according to driving of the piezoelectric element,
wherein the piezoelectric element includes an insulating film
formed on the vibration film, a first electrode film formed on the
insulating film, a piezoelectric layer formed on the first
electrode film, and a second electrode film formed on the
piezoelectric layer, and wherein the insulating film includes a
lower insulating film formed on the vibration film and an upper
insulating film which is formed on the lower insulating film with
the same material as that of the lower insulating film, but has a
different crystal structure.
2. The liquid ejecting head according to claim 1, wherein the lower
insulating film is formed by a sputtering method, and the upper
insulating film is formed by a liquid-phase method.
3. The liquid ejecting head according to claim 2, wherein the upper
insulating film is formed to have a film thickness within a range
of 50 nm to 100 nm.
4. The liquid ejecting head according to claim 2, wherein the lower
insulating film is formed to have a film thickness within a range
of 20 nm to 50 nm, and the insulating film is formed to have a film
thickness within a range of 100 nm to 150 nm.
5. The liquid ejecting head according to claim 2, wherein the
surface roughness Ra on the upper insulating film is equal to or
more than 0.7 nm.
6. The liquid ejecting head according to claim 2, wherein yttrium
of 10% or less is added to the upper insulating film which is
formed by the liquid-phase method.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present invention relates to a liquid ejecting head, and
particularly, to a liquid ejecting head which is a useful for
realizing high density of a piezoelectric element.
[0003] 2. Related Art
[0004] A piezoelectric element, which is displaced by applying a
voltage, is mounted on, for example, a liquid ejecting head
ejecting liquid droplets, or the like. As such a liquid ejecting
head, for example, a recording head of an ink jet type
(hereinafter, also referred to as recording head) is known, in
which a part of a pressure generating chamber communicating with a
nozzle opening is formed of a vibration film. In addition, the
recording head discharges the ink droplets from nozzle openings by
pressurizing ink which fills an inside of the pressure generating
chamber in which the vibration film is deformed due to the
piezoelectric element.
[0005] In this type of the recording head, in order to accomplish
displacement of the vibration film when realizing a high-density of
the piezoelectric element disposed on an insulating film, for
example, an insulating film formed as a zirconia film needs to be
thin.
[0006] JP-A-2005-260003 discloses a technology for improving
characteristics of the piezoelectric layer by controlling the
surface roughness of the zirconia film when regulating a film
formation condition of the zirconia film, which is the insulating
film.
[0007] FIG. 8 is a graph illustrating a correlation of the surface
roughness Ra of the insulating film and (100) alignment ratio of a
piezoelectric layer (PZT) crystal. As illustrated in the drawing,
the crystal becomes good when the alignment ratio of the
piezoelectric layer increases as a numerical value of the surface
roughness Ra also increases. It suggests that the insulating film
can be thin while controlling the crystal properties of the
piezoelectric layer when the surface roughness Ra increases. That
is, when the insulating film can be realized to be thin, the
displacement thereof according to driving of the piezoelectric
element can be great.
[0008] However, as disclosed in JP-A-2005-260003, the surface
roughness Ra is less likely to be controlled using only a film
formation condition of the insulating film (zirconia film), and the
crystal properties of the piezoelectric layer is less likely to be
improved. That is, in a technology of the related art disclosed in
JP-A-2005-260003, or the like, a film thickness of the insulating
film needs to be thin in order to realize a high density of the
piezoelectric element; however, the surface roughness Ra is not
increased when the film thickness thereof becomes thin, and the
alignment ratio of the piezoelectric layer becomes small.
Therefore, the film thickness of the insulating film is required to
be large.
SUMMARY
[0009] An advantage of some aspects of the invention is to provide
a liquid ejecting head including a piezoelectric element, which
makes an insulating film thin while controlling the crystal
properties of the piezoelectric layer.
[0010] According to an aspect of the invention, there is provided a
liquid ejecting head including a piezoelectric element that is
disposed on a flow passage formation substrate, and discharging
liquid from nozzle openings through the nozzle openings by
pressurizing the liquid which fills an inside of a pressure
generating chamber due to displacement of a vibration film
according to driving of the piezoelectric element, in which the
piezoelectric element includes an insulating film formed on the
vibration film, a first electrode film formed on the insulating
film, a piezoelectric layer formed on the first electrode film, and
a second electrode film formed on the piezoelectric layer, and the
insulating film includes a lower insulating film formed on the
vibration film and an upper insulating film which is formed on the
lower insulating film with the same material as that of the lower
insulating film, but has a different crystal structure.
[0011] In this case, the insulating film is configured to have the
lower insulating film which is formed on the vibration film and the
upper insulating film which is formed on the lower insulating film.
Moreover, the upper insulating film is made of the same material as
that of the lower insulating film but has a different crystal
structure, and thus the surface roughness Ra of the insulating film
can be increased. As a result, the alignment ratio of the
piezoelectric layer formed on the insulating film can be increased
through the first electrode film, and the insulating film can be
thin while controlling the crystal properties of the piezoelectric
layer. Therefore, the displacement according to driving of the
piezoelectric element can be significantly increased.
[0012] In the liquid ejecting head, the lower insulating film may
be formed by a sputtering method, and the upper insulating film may
be formed by a liquid-phase method. The lower insulating film
formed by the sputtering method is formed as columnar particles,
and spreading of Pb from the piezoelectric layer may be
appropriately suppressed. Meanwhile, the upper insulating film
formed by the liquid-phase method may be formed as small-diameter
particles, and have a low Young's modulus, so that the crystal
properties of the piezoelectric layer can be improved.
[0013] In the liquid ejecting head, the upper insulating film
preferably is formed to have a film thickness within a range of 50
nm to 100 nm. The lower insulating film preferably is formed to
have a film thickness within a range of 20 nm to 50 nm, and the
insulating film preferably is formed to have a film thickness
within a range of 100 nm to 150 nm. Accordingly, the film thickness
of the insulating film can be formed to be thin up to substantially
125 nm compared to substantially 400 nm thickness thereof in the
related art.
[0014] In the liquid ejecting head, the surface roughness Ra on the
upper insulating film preferably is equal to or more than 0.7 nm.
Accordingly, a great surface roughness Ra is obtained, and the
alignment properties of the piezoelectric layer can be 90%, or
more. In addition, yttrium of 10% or less preferably is added to
the upper insulating film which is formed by the liquid-phase
method. Stabilization of the crystal of the upper insulating film
can be realized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention will be described with reference to the
accompanying drawings, wherein like numbers reference like
elements.
[0016] FIG. 1 is an exploded perspective view of a recording head
according to an embodiment.
[0017] FIGS. 2A and 2B are respectively a plan view and a sectional
view of the recording head according to the embodiment.
[0018] FIG. 3 is a schematic view illustrating two layers of an
insulating film having different crystal structures.
[0019] FIGS. 4A, 4B, 4C, and 4D are sectional views illustrating a
manufacturing process of the recording head according to the
embodiment.
[0020] FIGS. 5A, 5B, and 5C are sectional views illustrating the
manufacturing process of the recording head according to the
embodiment.
[0021] FIGS. 6A, 6B, and 6C are sectional views illustrating the
manufacturing process of the recording head according to the
embodiment.
[0022] FIG. 7 is sectional view illustrating the manufacturing
process of the recording head according to the embodiment.
[0023] FIG. 8 is a graph illustrating a correlation of a roughness
of the insulating film and an alignment ratio of a piezoelectric
layer.
DESCRIPTION OF EXEMPLARY EMBODIMENT
[0024] Hereinafter, the invention will be described in detail based
on an embodiment.
[0025] FIG. 1 is an exploded perspective view illustrating a
recording head of an ink jet type according to the embodiment of
the invention, and FIGS. 2A and 2B are respectively a plan view and
a sectional view of FIG. 1. As illustrated in FIG. 1 to FIG. 2B, a
flow passage formation substrate 10 is formed of a silicon single
crystal substrate of an alignment (110) in the embodiment, and a
vibration film 50, which is formed of a silicon dioxide made by
thermal oxidization in advance, is formed on one surface of the
flow passage formation substrate. In the flow passage formation
substrate 10, a plurality of pressure generating chambers 12, which
are formed by an anisotropic etching from the other surface side
thereof and are divided by partition walls 11, are arranged in a
width direction thereof. In addition, a communication portion 13 is
formed in a region outside of a longitudinal direction of the
pressure generating chamber 12 of the flow passage formation
substrate 10, and the communication portion 13 and each of the
pressure generating chamber 12 communicate with each other through
ink supply passages 14 which are respectively formed in each of the
pressure generating chamber 12. Moreover, the communication portion
13 constitutes a part of a manifold which is a common ink chamber
of the pressure generating chamber 12 by communicating with a
manifold portion of a protective substrate to be described later.
The ink supply passage 14 is formed with a width narrower than the
pressure generating chamber 12, and a flow passage resistance of
ink, which flows from the communication portion 13 to the pressure
generating chamber 12, is constantly maintained.
[0026] In addition, the nozzle plate 20 in which nozzle openings
21, which communicates near an end portion on an opposite side of
the ink supply passage 14 of each pressure generating chamber 12,
are perforated, is fixed in an opening surface side of the flow
passage formation substrate 10 through a mask film to be described
later using an adhesive, heat welding film, or the like. Also, the
nozzle plate 20 has a thickness of, for example, 0.01 mm to 1 mm,
and linear expansion coefficient thereof is 300.degree. C. or less.
The nozzle plate is formed of, for example, a glass ceramic which
is 2.5 to 4.5[.times.10.sup.-6/.degree. C.], the silicon single
crystal substrate, stainless steel, or the like.
[0027] Meanwhile, as described above, for example, a vibration film
50 which is formed of the silicon dioxide (SiO.sub.2) having
substantially 0.5 .mu.m thickness is formed on the opposite side of
the opening surface side of the flow passage formation substrate
10, and an insulating film 55 which is formed of zirconium oxide
(ZrO.sub.2) are formed on the vibration film 50. The insulating
film 55 in the embodiment is a film of two layers structure in
which a lower insulating film and an upper insulating film are
included. The lower insulating film is formed on the vibration film
50, and an upper insulating film is formed on the lower insulating
film with the same material as that of the lower insulating film,
but has a different crystal structure. The insulating film 55 is
formed by being over-coated with the same material (zirconium in
the embodiment) as that of the insulating film 55 in a liquid-phase
method. In this case, the surface roughness Ra of the insulating
film 55 which is over-coated by the liquid-phase method is
preferably 0.7 nm or more and less than 3 nm. When the surface
roughness Ra is set to 0.7 nm or more, as illustrated in FIG. 8, an
alignment ratio of a piezoelectric layer 70 can be 90% or more. In
addition, as seen from the above, it is preferable that yttrium of
10% or less is added to the insulating film 55 formed by the
liquid-phase method. This process is performed in order to
stabilize the crystal of the insulating film 55.
[0028] The insulating film 55 in the embodiment as described above
is formed by over-coating a zirconium film which is the same
material as that of the insulating film 55 in the liquid-phase
method. As a result, as schematically illustrated in FIG. 3, the
insulating film 55 in the embodiment includes the two-layer
structure in which a lower insulating film 55A and an upper
insulating film 55B are included. The lower insulating film 55A is
formed on the vibration film 50 (for example, refer to FIG. 1), and
the upper insulating film 55B is formed on the lower insulating
film 55A. Also, in the embodiment, the lower insulating film 55A is
formed by a sputtering method, and the upper insulating film 55B is
formed by a liquid-phase method.
[0029] As a result, the lower insulating film 55A formed by the
sputtering method includes the crystal structure in which columnar
particles are densely aggregated so as to be capable of
appropriately suppressing spreading of Pb from the piezoelectric
layer 70. Meanwhile, the upper insulating film 55B formed by the
liquid-phase method can be a flexible film having a low Young's
modulus, which includes a crystal structure in which small-diameter
particles are sparsely aggregated. Here, these films are formed so
that a relationship of a film thickness t1 of the lower insulating
film 55A>a film thickness t2 of the upper insulating film 55B is
satisfied.
[0030] Here, the film thickness of the insulating film 55 is formed
within a range of 100 nm to 150 nm. More details, the film
thickness of the upper insulating film 55B is formed within a range
of 50 nm to 100 nm as a reference value of 70 nm, and the film
thickness of the lower insulating film 55A is formed within a range
of 20 nm to 50 nm. Therefore, the lower insulating film 55A and the
upper insulating film 55B are formed so that a total film thickness
of both is within a range of 100 nm to 150 nm as a reference value
of 125 nm. Accordingly, in the related art, the film thickness of
the insulating film 55 which is substantially 400 nm can be thin to
become substantially 125 nm.
[0031] Moreover, in the embodiment, a film which is formed by the
sputtering method is referred to as the lower insulating film 55A,
and a film which is formed by the liquid-phase method is referred
to as the upper insulating film 55B; however, because of a
relationship thereof, as described above, both of a merit of a film
formation in the sputtering method and a merit of a film formation
in the liquid-phase method can be obtained. However, a vertical
relationship between the lower insulating film 55A and the upper
insulating film 55B is not necessarily limited to the embodiment.
It does not matter when the vertical relationship may be reversed.
In short, the insulating film 55 may include the two-layer
structure in which the lower insulating film and the upper
insulating film, which is formed on the lower insulating film with
the same material as that of the lower insulating film but has a
different crystal structure, are formed.
[0032] On the insulating film 55, a piezoelectric element 300 is
formed in which a first electrode film 60 which is a lower
electrode film, the piezoelectric layer 70, and a second electrode
film 80 which is an upper electrode film are multilayered by a
process to be described later. Here, the piezoelectric element 300
is a part which includes the first electrode film 60, the
piezoelectric layer 70, and the second electrode film 80. In
general, an electrode in any one of the piezoelectric element 300
is set to a common electrode, and an electrode in the other thereof
and the piezoelectric layer 70 are formed in each of the pressure
generating chambers 12 by patterning. Also, here, a part, which is
configured to have any patterned electrode and the piezoelectric
layer 70, so that a piezoelectric strain is generated due to
applying of the voltage to both electrodes, is set to a
piezoelectric active portion. In the embodiment, the first
electrode film 60 is set to a common electrode of the piezoelectric
element 300, and the second electrode film 80 is set to an
individual electrode of the piezoelectric element 300; however, it
does not matter when these films are reversed because of setting of
driving circuits or wires. In any case, the piezoelectric active
portion is formed in each of the pressure generating chambers 12.
In addition, in the embodiment, the vibration film 50, the
insulating film 55, and the first electrode film 60 function as a
vibration plate.
[0033] In addition, lead electrodes 90 are respectively connected
to each of the second electrode films 80 of the piezoelectric
elements 300, and a voltage is selectively applied to each of the
piezoelectric elements 300 through the lead electrodes 90.
[0034] In addition, in a surface of the piezoelectric element 300
side on the flow passage formation substrate 10, a protection
substrate 30 including a piezoelectric element holding portion 31
is bonded to a region facing the piezoelectric element 300 using an
adhesive. The piezoelectric element 300 is formed in the
piezoelectric element holding portion 31 so as to be protected in a
state in which an external circumstance does not have an influence
thereon. Further, in the protection substrate 30, a manifold
portion 32 is provided on a region corresponding to the
communication portion 13 of the flow passage formation substrate
10. In the embodiment, the manifold portion 32 is formed in a
juxtaposing direction of the pressure generating chamber 12 by
communicating with the protection substrate 30 in a thickness
direction in the embodiment, and constitutes a manifold 100 which
is a common ink chamber of each of the pressure generating chamber
12 by penetrating the communication portion 13 of the flow passage
formation substrate 10 as described above.
[0035] In a region between the piezoelectric element holding
portion 31 and the manifold portion 32 of the protection substrate
30, a through hole 33 which penetrates the protection substrate 30
in a thickness direction is provided, and a part of the first
electrode film 60 and a tip end portion of the lead electrode 90 in
the through hole 33 are exposed. It is not illustrated; however,
the other end of a connection wire in which one end thereof, which
is connected to a driving IC, is connected to the first electrode
film 60 and the lead electrode 90.
[0036] Moreover, as a material of the protection substrate 30, for
example, a glass, a ceramic material, a metal, a resin, and the
like are exemplified, but the protection substrate 30 is more
preferably made of a material having a thermal expansion ratio
thereof substantially similar to that of the flow passage formation
substrate 10. In the embodiment, the protection substrate 30 is
formed of a silicon single crystal substrate which is the same
material as that of the flow passage formation substrate 10.
[0037] In addition, a compliance substrate 40, which is configured
to have a sealing film 41 and a fixing plate 42, is bonded onto the
protection substrate 30. The sealing film 41 is made of a material
having flexibility and low rigidity (for example, polyphenylene
sulfide (PPS) film having 6 .mu.m thickness), and one surface of
the manifold portion 32 is sealed with the sealing film 41. In
addition, the fixing plate 42 is made of a hard material such as a
metal (for example, stainless steel (SUS) having 30 .mu.m
thickness, or the like). Since a region facing the manifold 100 of
the fixing plate 42 is an opening portion 43 which is completely
removed in a thickness direction, one surface of the manifold 100
is sealed with only the sealing film 41 having flexibility.
[0038] The recording head of an ink jet type of the embodiment
discharges ink by processes as follows: an inside thereof is filled
with the ink throughout from the manifold 100 to the nozzle opening
21 after absorbing the ink from an external ink supplying unit
which is not illustrated; in response to a recording signal from
the driving IC which is not illustrated, a voltage is applied
between each of the first electrode films 60 and the second
electrode films 80 corresponding to the pressure generating chamber
12; and the vibration film 50, the insulating film 55, the first
electrode film 60, and the piezoelectric layer 70 are bent and
deformed. Therefore, the pressure inside the pressure generating
chamber 12 is increased, and the ink is discharged from the nozzle
opening 21.
[0039] Hitherto, according to the recording head of the embodiment,
the insulating film 55 is configured to have the lower insulating
film 55A formed on the vibration film 50 and the upper insulating
film 55B formed on the lower insulating film 55A, in addition, the
upper insulating film 55B is made of the same material as that of
the lower insulating film 55A but has a different crystal
structure, thereby making it possible to increase the surface
roughness Ra of the insulating film 55. As a result, the alignment
ratio of the piezoelectric layer 70 formed on the insulating film
55 can be increased through the first electrode film 60, and thus
the insulating film 55 can be made thin while controlling the
crystal properties of the piezoelectric layer 70. For this reason,
displacement is significantly increased according to driving of the
piezoelectric element.
[0040] Next, a manufacturing method of the recording head of an ink
jet type described above (hereinafter, also referred to as
recording head) will be described with reference to FIG. 4A to FIG.
7. Moreover, FIG. 4A to FIG. 7 are sectional views of the pressure
generating chamber 12 taken along the longitudinal direction.
First, as illustrated in FIG. 4A, a wafer 110 for flow passage
formation substrate which is a silicon wafer is thermally oxidized
at substantially 1100.degree. C. of a diffusion furnace, and the
silicon dioxide film 51 constituting the vibration film 50 is
formed on a surface thereof. Moreover, in the embodiment, as the
flow passage formation substrate 10, a silicon wafer having a
relatively great film thickness of substantially 625 .mu.m and a
relatively high rigidity is used.
[0041] Next, as illustrated in FIG. 4B, the insulating film 55 made
of zirconium oxide is formed on the vibration film 50 (silicon
dioxide film 51). Specifically, a zirconium (Zr) layer is formed on
the vibration film 50 (silicon dioxide film 51). Subsequently, the
insulating film 55 which is made of a zirconium oxide is formed by
thermally oxidizing the zirconium layer. The insulating film 55 in
the embodiment is formed as a film having two-layer structure in
which the lower insulating film 55A and the upper insulating film
55B are included. The lower insulating film 55A is formed on the
vibration film 50 as described above, and the upper insulating film
55B is formed on the lower insulating film 55A with the same
material as that of the lower insulating film 55A but has a
different crystal structure.
[0042] Next, as illustrated in FIG. 4C, for example, the first
electrode film 60 which is made of at least platinum and iridium is
formed on the entire surface of the insulating film 55 by the
sputtering method, or the like, and then the first electrode film
60 is patterned into a predetermined shape. Moreover, the surface
roughness Ra of the first electrode film 60 depends on the surface
roughness Ra of the insulating film 55. In the embodiment, the
insulating film 55 is configured to have the two-layer structure so
as to increase the surface roughness Ra, and thus, alignment
properties of the piezoelectric layer 70 formed on the first
electrode film 60 can be reliably maintained.
[0043] Next, as illustrated in FIG. 4D, titanium (Ti) is applied on
the first electrode film 60 and the insulating film 55 twice or
more by the sputtering method, for example, a DC sputtering method
(applied twice in the embodiment), and thus, a continuous type
titanium seed layer 65 having a predetermined thickness is formed.
The titanium seed layer 65 is preferably formed with a film
thickness which is within a range of 1 nm to 8 nm. When the
titanium seed layer 65 is formed to have such a thickness as
described above, the crystal properties of the piezoelectric layer
70, which is formed in a process to be described later, can be
improved.
[0044] Next, for example, the piezoelectric layer 70 which is made
of a lead zirconate titanate (PZT) is formed on the titanium seed
layer 65 formed as described above. In the embodiment, the
piezoelectric layer 70 made of a metal oxide is obtained by
applying and drying a so-called sol, which is obtained by
dissolving and dispersing an organic metal material, and gelling
the resultant, and further firing the resultant at a high
temperature. Therefore, the piezoelectric layer 70 made of PZT is
formed by a so-called sol-gel method.
[0045] After forming the piezoelectric layer 70, as illustrated in
FIG. 5A, for example, the second electrode film 80 made of iridium
is formed on the entire surface of the wafer 110 for flow passage
formation substrate. Subsequently, as illustrated in FIG. 5B, the
piezoelectric element 300 is formed by patterning the piezoelectric
layer 70 and the second electrode film 80 on a region facing each
of the pressure generating chambers 12. Next, the lead electrode 90
is formed. Specifically, as illustrated in FIG. 5C, for example, a
metal layer 91 made of gold (Au), or the like is formed throughout
the entire surface of the wafer 110 for flow passage formation
substrate. After that, the lead electrode 90 is formed by
patterning the metal layer 91 in each of the piezoelectric elements
300 for example, through a mask pattern made of a resist, or the
like (not illustrated).
[0046] Next, as illustrated in FIG. 6A, a wafer 130 for protection
substrate, which is a silicon wafer and functions as a plurality of
the protection substrates 30, is bonded to the piezoelectric
element 300 side of the wafer 110 for flow passage formation
substrate. Moreover, the wafer 130 for protection substrate has a
thickness of, for example, substantially 400 .mu.m, and thus, the
rigidity of the wafer 110 for flow passage formation substrate is
significantly improved by being bonded to the wafer 130 for
protection substrate.
[0047] Next, as illustrated in FIG. 6B, after the wafer 110 for
flow passage formation substrate is ground to have some thickness,
and is further wet-etched using nitrohydrofluoric acid, therefore,
the wafer 110 for flow passage formation substrate becomes a
predetermined thickness. For example, in the embodiment, the wafer
110 for flow passage formation substrate is etched so as to have a
thickness of substantially 70 .mu.m.
[0048] Next, as illustrated in FIG. 6C, for example, the mask film
52 made of silicon nitride (SiN) is newly formed on the wafer 110
for flow passage formation substrate, and is patterned to be a
predetermined shape. Also, an anisotropic etching is performed on
the wafer 110 for flow passage formation substrate through the mask
film 52, and as illustrated in FIG. 7, the pressure generating
chamber 12, the communication portion 13, the ink supply passage
14, and the like are formed on the wafer 110 for flow passage
formation substrate.
[0049] After that, an unnecessary portion of an outer circumference
edge portion of the wafer 110 for flow passage formation substrate
and the wafer 130 for protection substrate is cut so as to be
removed, for example, by dicing. Also, the nozzle plate 20 in which
the nozzle opening 21 is perforated is bonded to a surface opposite
to the wafer 130 for protection substrate of the wafer 110 for flow
passage formation substrate, and the compliance substrate 40 is
bonded to the wafer 130 for protection substrate 130. Then, the
wafer 110 for flow passage formation substrate, or the like is
divided into the flow passage formation substrate 10, or the like
of a size of one chip as illustrated in FIG. 1, and thus the
recording head of an ink jet type in the embodiment is made.
Other Embodiment
[0050] Hitherto, one embodiment of the invention is described;
however, the invention is not limited to the embodiment described
above. For example, in the embodiment described above, as an
example of a head using a liquid ejecting apparatus, the recording
head of an ink jet type is exemplified; however, the invention is
widely used for general liquid ejecting heads, and can be applied
to an apparatus which ejects liquid other than the ink, of course.
As the others except the liquid ejecting head, for example, there
are various recording heads used for an image recording apparatus
such as a printer, color material ejecting heads used for
manufacturing color filters such as liquid crystal display,
electrode material ejecting heads used for forming electrodes of an
organic EL display, a field emission display (FED), and the like,
bio-organic material ejecting heads used for manufacturing bio
chips, and the like. In addition, the invention can be used for not
only an actuator which is mounted on the liquid ejecting head
(recording head of ink jet type) as a liquid discharging unit, but
also for actuator apparatus mounted on all apparatuses. For
example, an actuator apparatus can be used for the heads described
above, and also used for sensors, and the like.
* * * * *